Implant and Method for Improving Coaptation of an Atrioventricular Valve

ABSTRACT

The invention relates to an implant and a method for improving coaptation of an atrioventricular valve, the atrioventricular valve having a first native leaflet, a second native leaflet and an annulus. The implant comprises a support structure and a flexible retention means mounted to the support structure to prevent prolapse of at least one of the first and the second native leaflet.

FIELD

The invention relates to an implant and a method for improvingcoaptation of an atrioventricular valve.

BACKGROUND

Atrioventricular valves are membranous folds that prevent backflow fromthe ventricles of the human heart into the atrium during systole. Theyare anchored within the ventricular cavity by chordae tendineae, whichprevent the valve from prolapsing into the atrium.

The chordae tendineae are attached to papillary muscles that causetension to better hold the valve. Together, the papillary muscles andthe chordae tendineae are known as the subvalvular apparatus. Thefunction of the subvalvular apparatus is to keep the valves fromprolapsing into the atria when they close. The opening and closure ofthe valves is caused by the pressure gradient across the valve.

The human heart comprises two atrioventricular valves, the mitral valveand the tricuspid valve. The mitral valve allows the blood to flow fromthe left atrium into the left ventricle. The tricuspid valve is locatedbetween the right atrium and the right ventricle. The mitral valve hastwo leaflets that are each divided into several scallops: the anteriorleaflet has three scallops (A1, A2, A3), the posterior leaflet has threescallops (P1, P2, P3). The tricuspid valve has three leaflets.Engagement of corresponding surfaces of the leaflets against each otheris decisive for providing closure of the valve to prevent blood flowingin the wrong direction. The closure forms a so called coaptation area.

Native heart valves become dysfunctional for a variety of pathologicalcauses. Failure of the leaflets to seal during ventricular systole isknown as malcoaptation, and may allow blood to flow backward through thevalve (regurgitation). Malcoaptation is often caused by a dilatation ofthe annulus. This is mainly due to an enlargement of the left atriumwith preserved posterior wall motion or in case of posterior myocardialinfarction due to posterior wall motion abnormalities leading toasymmetric annular dilatation. Another reason is a restriction in motionor an excessive motion of the leaflet structures. Another cause ofsevere regurgitation is the local elongation or rupture of chordaeresulting in a prolapse of parts of the leaflet. Heart valveregurgitation can result in cardiac failure, decreased blood flow, lowerblood pressure, and/or a diminished flow of oxygen to the tissues of thebody. Mitral regurgitation can also cause blood to flow back from theleft atrium to the pulmonary veins, causing congestion and backwardfailure.

Some pathologies of atrioventricular valves, such as malcoaptation,often require reconstruction of the valvular and subvalvular apparatusas well as redesigning the enlarged annulus. Sometimes a completesurgical replacement of the natural heart valve with heart valveprosthesis is necessary. There are two main types of artificial heartvalves: the mechanical and the biological valves. The mechanical-typeheart valve uses a pivoting mechanical closure supported by a basestructure to provide unidirectional blood flow. The tissue-type valveshave flexible leaflets supported by a base structure and projecting intothe flow stream that function similar to those of a natural human heartvalve and imitate their natural flexing action to coapt against eachother. Usually two or more flexible leaflets are mounted within aperipheral support structure made of a metallic or polymeric material.In transcatheter implantation the support within the annulus may be inthe form of a stent, as is disclosed in US 2011/0208298 A1.

In order to provide enough space for the artificial leaflets to workproperly, the peripheral support is positioned in the native valve so asto force the native leaflets apart. To this end and in order to provideappropriate anchoring of the peripheral support within the native valve,the same is fixed to the native leaflets by suitable means. However, insome applications, such as with mitral valves, fixing the peripheralsupport to the native anterior leaflet and dislocating the same from itsnatural position may cause an obstruction of the outflow tract and ofthe aortic valve, which is located in the left ventricle immediatelyadjacent the anterior leaflet.

The gold standard for treating mitral regurgitation is to repair themitral apparatus including leaflets and the subvalvular apparatus and toreshape the mitral annulus (Carpentier technique). If repair is notpossible an excision of the valve including parts of the subvalvularapparatus is performed with subsequent implantation of a heart valveprosthesis. This is necessary particularly when the valve is destructedby inflammation. Although in most instances a complete excision of thedestroyed valve is necessary, sometimes a partial replacement ispossible. A clinically used mitral valve restoration system (Mitrofix®)replaces only the posterior leaflet with a rigid prosthesis mimicking afixed posterior leaflet allowing the natural anterior leaflet to coapt.This prosthesis is also sewn into the position of the destroyedposterior aspect of the annulus. This requires open heart surgery andextended cardiac arrest.

Recent trends focus on less invasive procedures to minimize surgicaltrauma and to perform transcatheter approaches including transatrial,transaortal or transapical procedures to replace or reconstructdysfunctional valves thus minimizing the need of or avoiding heart lungmachine and cardiac arrest. Whereas this is a common procedure in aorticvalves nowadays, only few mitral valves insufficiencies are corrected bypercutaneous or transapical procedures. Most of these concepts areredesigning and remodeling artificially the mitral annulus to allowcoaptation or to enforce coaptation by fixing both leaflets togetherwith a clip reducing mitral regurgitant flow. Percutaneously ortransapically deployed valve prostheses are difficult to anchor due tothe special anatomy of the mitral valve and the vicinity of the anteriorleaflet to the aortic outflow tract.

SUMMARY

Therefore, it is an object of the instant invention to provide animproved implant for improving coaptation of an atrioventricular valveand to prevent prolapse of the native leaflet into the atrium. Inparticular, it is an object of the invention to provide an implant thatdoes not involve the risk of stenosis of the aortic valve.

It is a further object of the invention to provide an implant that canbe easily deployed to the target site.

The invention generally provides improved medical implants and methodsfor the treatment of regurgitation in atrioventricular valves, inparticular mitral valves. In some embodiments, the invention provides amedical implant that provides retention means cooperating with at leastone of the first and second native leaflet in order to prevent aprolapse thereof into the atrium. Therefore, the implant assists thefunction of a damaged or otherwise malfunctional native leaflet.However, the damaged or otherwise malfunctional native leaflet is notphysically removed. Rather, the damaged or otherwise malfunctionalnative leaflet is left in the valve.

The implant provides retention means that prevent the damaged orotherwise malfunctional native leaflet from prolapsing into the atrium.The retention means may or may not comprise an artificial leaflet thatis arranged adjacent the native leaflet. The retention means maycomprise a flexible net or flexible wires or yarns that cooperate withthe artificial leaflet or the native leaflet in order to preventprolapse. In case an artificial leaflet is provided, the damaged orotherwise malfunctional native leaflet may support the function of theartificial leaflet or parts thereof.

In some embodiments, the retention means are flexible in order to allowthe native and/or artificial leaflet to perform its usual function andcoapt with the other native leaflet.

In some embodiments, the invention provides an implant comprising asupport structure configured to be arranged on and fixed to the annulusor to at least one of the first and second native first leaflets, theimplant further comprising retention means fixed to the supportstructure so as to prevent prolapse of the at least one native leafletor parts thereof (e.g. P1, P2, P3), wherein the support structurecomprises an upper support element to be arranged on a superior surfaceof the annulus or of the at least one native leaflet and a lower supportelement to be arranged on an inferior surface of the annulus or of theat least one native leaflet, the upper and the lower support elementseach comprising connection means cooperating which each other forinterconnecting the upper and the lower support element while clamping asection of the annulus or of the at least one native leaflet between theupper support element and the lower support element, wherein at leastone connection means comprises a penetrating section configured topenetrate the annulus or the at least one native leaflet for beingconnected with the other connection means.

Thus, the support structure is fixed on the annulus of the native valveor on at least one of the first and second native leaflet. Preferably,the support structure is fixed only to the first native leaflet or thesecond native leaflet. In case of an implant configured for mitralvalves, the first native leaflet is a posterior leaflet of the mitralvalve and the second native leaflet is an anterior leaflet of the mitralvalve. In case the retention means comprise an artificial leaflet, thelatter is preferably configured as an artificial posterior leaflet andreplaces and/or supports the function of the native posterior leaflet.The artificial posterior leaflet is preferably shaped such as to improvecoaptation with the native anterior leaflet and may be adjustedindividually based on patient-specific image data obtained by imagingtechniques.

In case of an implant configured for tricuspid valves, the first nativeleaflet is an anterior leaflet of the tricuspid valve and the secondnative leaflet is a posterior leaflet and the third leaflet is theseptal leaflet of the tricuspid valve. In case the retention meanscomprise an artificial leaflet, the latter is configured to replace thefunction of the native anterior or posterior leaflet. The artificialanterior or posterior leaflet or the combination of both is preferablyshaped such as to improve coaptation with the native anterior andposterior leaflet.

The support structure is preferably fixed only to one leaflet, eitherthe first or the second leaflet, or only to that partial region of theannulus, from which the first or the second leaflet emerges. Further,the retention means are configured to cooperate with and preventprolapse of only the leaflet, to which the support structure is fixed.

The support structure is configured to carry the retention means and tohold the retention means in a position, in which it can retain the atleast one native leaflet to coapt with the native second leaflet.

In order to associate the implant to the annulus or the native leaflet,the support structure comprises an upper support element and a lowersupport element configured to squeeze a section of the annulus or thenative leaflet between them in order to avoid improper paravalvularleakage and regurgitation.

The upper support element preferably is substantially C-shaped,U-shaped, semicircular or circular so as to conform to the shape of theannulus or a section of the annulus. In order to stabilize the uppersupport element, the upper support element preferably comprises bracingmeans for applying a radial bracing force across the annulus and theadjacent atrial wall. The bracing force acts so as to spread apart theannulus, so as to firmly hold the upper support element relative to theannulus.

In some embodiments of the invention, the upper support element extendsonly over a segment of the annulus.

The upper and the lower support elements preferably comprise a foldablestructure, so that it may be advanced to the valve in a folded state.Preferably, the upper and the lower support elements comprise curvedwires made of a shape memory alloy, such as nitinol. Preferably, thecurved wires are in the shape of at least two wings extending outwardlyfrom a central support.

In some embodiments, the implant further comprises a tubular housing,wherein the support structure and the retention means are deployablefrom a first position, in which the support structure and the retentionmeans are arranged within the tubular housing, into a second position,in which the support structure is deployed. In this way, the implant canbe easily deployed to the heart by minimal invasive surgery orendovascular approaches. In particular, the tubular housing ispreferably advanced into the heart by means of a catheter or adeployment instrument transatrially, transseptally, transfemorally ortransapically.

Preferably, the support structure and the retention means are configuredto be deployed from a folded or rolled-up state into an extended state.In the folded or rolled-up state, the structures may easily be advancedto the heart transcatheterally or transapically.

Preferably, the tubular housing comprises two half-shells, a firsthalf-shell housing the upper support element and a second half-shellhousing the lower support element. Alternatively, the tubular housingmay comprise more than two shells, each extending over a segment of thecircular cross section of the tubular housing and together forming thetubular housing.

The configuration of the tubular housing with two or more shells allowsfor a selective deployment of a corresponding number of elements of theimplant. A preferred way of deploying the elements of the implant isachieved by having the shells, in particular the first and secondhalf-shells, arranged to swing open. The swinging open of the shellsallows to open the tubular housing for enabling a deployment of theimplant.

Preferably, the upper and the lower support elements of the implant arehoused in the tubular housing in a separate, not interconnected manner.Thus, the upper and the lower support elements, each preferably arrangedin an own shell of the tubular housing, can easily be deployedseparately and be separately brought in the correct position thatsubsequently allows their connection with each other.

Preferably, the first and second half-shells are arranged at the distalend of a deployment instrument, such as a steerable instrument or acatheter. The instrument may have a catheter-like tube that may beadvanced transapically, transaortically or transatrially into the heartand that carries the tubular housing on its distal end. The proximal endof the deployment instrument, which is held by the surgeon orinterventionist, may preferably be provided with actuation meanscooperating with the shells of the tubular housing and with the upperand the lower support structure in order to control the swinging open ofthe shells and of the displacement, the deployment and the extension ofthe support elements.

In some embodiments, the retention means comprise an artificial leafletarranged on the upper support element. Alternatively, or in addition,the retention means comprise a flexible net or a plurality of flexiblewires or yarns. The flexible net or the plurality of flexible wires oryarns cover an area that corresponds substantially to the area of thenative leaflet and/or the artificial leaflet to be held by the retentionmeans. In some embodiments, the flexible net, wires or yarns may beembedded into or fixed to the artificial leaflet. Preferably, theretention means, in particular the flexible net, wires or yarns, arefixed to the native leaflet by means of at least one fixation element atthe hinge point between the coaptation and free part of the nativevalve.

The artificial leaflet may be made of a biocompatible material, such aspolyethylene or polyurethane, polyfluorethylen (Goretex®) or fromnatural tissue such as heterologic pericardium.

In a preferred embodiment the artificial net or leaflet structure isfixed with a second fixation mechanism at the hinge point of theprolapsing leaflet at the coaptation line with the native (prolapsing)leaflet part.

In order to fix the retention means on the supporting structure, apreferred embodiment provides that the lower support element carries atleast one holding arm for holding the retention means. The holding armmay be configured in the form of a hook. The free end of the armpreferably carries an eye for drawing a wire or a yarn of the retentionmeans therethrough.

Preferably, the retention means, on one end thereof, are connected tothe lower support structure and, on the other end thereof, are connectedto the upper support structure. In its region between the both ends theretention means cooperate with the native leaflet in order prevent aprolapse.

Preferably, the holding arm or the hook is configured to be adjustablein length in order to allow for some flexibility in application.

According to a further aspect the invention refers to a method ofimproving coaptation of an atrioventricular valve, the atrioventricularvalve having an annulus, a first native leaflet and a second nativeleaflet, the method comprising:

-   -   providing an implant comprising a support structure and        retention means fixed to the support structure, wherein the        support structure comprises an upper support element and a lower        support element, the implant being arranged in a tubular housing        with the upper and the lower support structure being in a folded        state, said tubular housing comprising a first and a second        half-shell, wherein the first half-shell houses the upper        support element and the second half-shell houses the lower        support element,    -   advancing the tubular housing into the heart,    -   swinging open the half-shells,    -   advancing the tubular housing with the implant so that the first        or the second native leaflet is arranged between the first and        the second half-shells,    -   unfolding the upper and the lower support structure,    -   fixing the upper and the lower support structure relative to the        annulus or to the first or second native leaflet, said fixing        step comprising interconnecting connection means of the upper        and the lower support elements thereby clamping a section of the        annulus or of said first or second native leaflet between the        upper support element and the lower support element, wherein at        least one connection means comprises a penetrating section that        penetrates the annulus or said first or second native leaflet        when being connected with the other connection means,    -   positioning the retention means so as to prevent prolapse of the        first or second native leaflet,    -   withdrawing the tubular housing from the heart.

Preferably, the tubular housing is advanced into the hearttransatrially, i.e. through the left atrium of the heart, transseptally,i.e. through the septum of the heart, transfemorally or transapically,i.e. through the apex of the heart or the aorta. The positioning isfacilitated by a steerable guiding element to maneuver the tubularhousing.

Preferably, the step of fixing the support structure comprisespositioning the upper support element on a superior surface of theannulus or the native leaflet and positioning the lower support elementon an inferior surface of the annulus or the native leaflet.

Preferably, said fixing step comprises, before interconnecting theconnection means, axially aligning the connection means with each otherby moving at least one of the connection means relative to the otherconnection means.

Preferably, said step of interconnecting the connection means comprisesmoving the connection means towards each other by a closing action ofthe half-shells.

Preferably, the step of connecting the connection means with each othercomprises penetrating the annulus or said first or second nativeleaflet. The penetration may be achieved by mechanic forces of apenetrating section of at least one connection means or by heat or byelectric current.

Preferably, said step of positioning the retention means comprisesadjusting a length of said retention means between one end thereof,which is connected to the lower support structure, and another endthereof, which is connected to the upper support structure.

Preferably, the native first leaflet is a native posterior leaflet of amitral valve and the second native leaflet is an anterior leaflet of themitral valve.

In a preferred embodiment retention means may be used, the size of whichis chosen to fit the individual patient by measurements of theprolapsing areas of the native valve. In particular, the size of thesupport structure and/or the size of the retention means may becalculated from the size of the prolapsing native leaflet part of thepatient.

Further, the length of the two arms of the support structure may bechosen as a function of individual measurements of the prolapsing areasof the valve.

Further, the retention means may be fixed to the native prolapsingleaflet at the coaptation line of the latter_([WM1]).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a human heart,

FIG. 2 is a top view of a mitral valve implant,

FIG. 3 is a side view of the mitral valve implant of FIG. 2,

FIG. 4 is a front view of the mitral valve implant of FIG. 2,

FIG. 5 is a perspective view of a deployment instrument for deployingthe mitral valve implant into the human heart,

FIG. 6 is a perspective view of the folded mitral valve implant arrangedin the deployment instrument,

FIG. 7 shows a cross sectional view of FIG. 5,

FIG. 8 to 13 are schematic illustrations of the consecutive steps ofdeploying and fixing a mitral valve implant in a human mitral valve.

DETAILED DESCRIPTION

Aspects of the present invention are disclosed in the followingdescription and related figures directed to specific embodiments of theinvention. Those skilled in the art will recognize that alternateembodiments may be devised without departing from the spirit or thescope of the claims. Additionally, well-known elements of exemplaryembodiments of the invention will not be described in detail or will beomitted so as not to obscure the relevant details of the invention.

It should be understood that the described embodiments are notnecessarily to be construed as preferred or advantageous over otherembodiments. Moreover, the terms “embodiments of the invention”,“embodiments” or “invention” do not require that all embodiments of theinvention include the discussed feature, advantage or mode of operation.

In FIG. 1 is a schematic illustration of a human heart 1 comprising theright ventricle 2, the right atrium 3, the left ventricle 4 and the leftatrium 5. The septum 6 divides the heart 1 in a right and a leftsection. The mitral valve 7 allows the blood to flow from the leftatrium 5 into the left ventricle 4. The tricuspid valve 8 is locatedbetween the right atrium 3 and the right ventricle 2. The ascendingaorta 9 originates at the orifice of the aortic valve 10. The mitralvalve 7 comprises an anterior leaflet and a posterior leaflet that areanchored within the left ventricular cavity by chordae tendineae 11,which prevent the valve 7 from prolapsing into the left atrium 5.

The mitral valve implant of the invention is configured to be deployedto the heart transcatheterally. In particular, the implant can bedelivered to the heart by means of a catheter transatrially, i.e.through the left atrium of the heart, transseptally, i.e. through theseptum 6 of the heart as depicted by line 12, transapically, i.e.through the apex of the heart as depicted by line 13, or through theascending aorta 9 as depicted by line 14.

During the implant procedure a balloon 15 is placed into the orifice ofthe mitral valve 7, which is inflated during systole and deflated duringdiastole to minimize regurgitant volume flow and to prevent severeinflow into the pulmonary veins.

As shown in FIG. 2, FIG. 3 and FIG. 4 the implant comprises a supportstructure 16 configured to be arranged on and fixed to the annulus or toat least one of the first and second native first leaflets of the mitralvalve. The support structure 16 comprises an upper support element 17 tobe arranged on a superior surface of the annulus or of the at least onenative leaflet and a lower support element 18 to be arranged on aninferior surface of the annulus or of the at least one native leaflet.The upper and the lower support elements 17 and 18 each comprises curvedwires 19,20 made of a shape memory alloy, such as nitinol. Preferably,the curved wires are in the shape of at least two wings extendingoutwardly from a central support 21,22. The implant further comprisingan arm 23 fixed to the lower support element 18 and having a bend 24 sothat the free end of the arm faces away from the lower support element18. The free end carries an eye 25 for holding one end of retentionmeans, such as a net or flexible wires or yarn. In the exemplarembodiment shown in FIGS. 2, 3 and 4, the retentions means comprises aplurality of yarns 36, each extending from the wings 19 to the eye 25.The yarns 36 are fixed to the wings 19 in a manner evenly distributedalong the length of the wings 19. Further, a yarn 37 is provided thatextends in a direction crossing the yarns 36. The yarns 37 is connectedto the yarns 36 at each crossing point, e.g. by gluing, bonding orwelding, so as to maintain a net-like structure, wherein the yarns 36are kept at a distance from each other. The function of the yarns 36 isto prevent prolapse of the at least one native leaflet.

In order to be able to fix the yarns 36 to the native leaflet a fixingelement 39 is provided on a centrally located yarn 36 at the hinge pointbetween the free valve surface and coaptation. In case of largerprolapses this mechanism of retention mechanisms can be doubled ormultiplied.

The deployment instrument for deploying the implant to the human heartis depicted in FIG. 5. The instrument 26 comprises a hand piece 27 and aflexible shaft 28, the distal free end of which is designed as a tubularhousing 29 comprising two half-shells, a first half-shell 30 housing theupper support element 17 and a second half-shell 31 housing the lowersupport element 18. The wings 19 and 20 are arranged in a folded stateso as to fit into the limited space provided inside the tubular housing29.

As can be seen in the illustration according to FIG. 6 and in the crosssection according to FIG. 7 the upper support element 17 and the lowersupport element 18 are arranged in the tubular housing so as to beoffset in the longitudinal direction and separated from each other. Theupper and the lower support elements 17 and 18 each comprise connectionmeans 32 and 33 cooperating which each other for interconnecting theupper and the lower support elements 17 and 18 while clamping a sectionof the annulus or of the at least one native leaflet between the uppersupport element 17 and the lower support element 18, wherein theconnection means 33 of the lower support element 18 are configured as apenetrating section, in particular a recessed pin 33 configured topenetrate the annulus or the at least one native leaflet for beingconnected with the connection means 32 of the upper support element 17.The connection means 32 are configured as a bore, into which the pin 33can immerse and fixed in the immersed position by means of a snapmechanism.

The first half-shell 30 and the second half-shell 31 are able to swingopen by means of hinges 34 and 35 (FIG. 7).

FIG. 8 to 13 are schematic illustrations of the consecutive steps ofdeploying and fixing a mitral valve implant in a human mitral valve 7.In a first step, the flexible shaft 28 together with the tubular housing29 is advanced into the left ventricle 4 of the human heart 1transseptally, transapically or through the ascending aorta 9. Further,the tubular housing 29 is advanced from the left atrium 4 towards themitral valve 7 in order to be placed in immediate vicinity of a leafletof the mitral valve.

In this position, the half shells 30 and 31 of the tubular housing 29are swung open, as can be seen in FIG. 9, and the tubular housing 29 isfurther advanced so that the leaflet of the mitral valve 7 is arrangedbetween the upper shell 30 and the lower shell 31.

As illustrated in FIG. 10, the shaft 28 with the tubular housing 29 maybe advanced into the left atrium 4 transseptally. Alternatively, asillustrated in FIG. 11, the shaft 28 with the tubular housing 29 may beadvanced into the left atrium 4 through the ascending aorta 9 and theaortic valve 10.

In a further step, illustrated in FIG. 12, the upper support element 17including the wings 19 have been deployed form the upper half-shell 30and the lower support element 18 including the wings 20 and the arm 23have been deployed from the lower half-shell 31 of the tubular housing29. The yarns 36 extend between the wings 19 and the arm 23. Inparticular, the yarns 36 extend from the wings 19 along the uppersurface (the surface facing the left atrium 5) of the leaflet of themitral valve 7, around the inner edge of the leaflet and down to the eye25 arranged on the free end of the arm 23.

In a further step, the upper support element 17 and the lower supportelement 18 are fixed to the annulus or to the first or second nativeleaflet of the mitral valve 7. The fixing step comprises clamping asection of the annulus or of the first or second native leaflet if themitral valve 7 between the upper support element 17 and the lowersupport element 18 by swinging the upper half-shell 30 and the lowerhalf-shell 31 towards each other. During the clamping step connectionmeans of the upper and the lower support elements 17,18 are connectedwith each other, wherein the pin 33 of the lower support element 18penetrates the annulus or the first or second native leaflet of themitral valve 7 and is introduced into the bore 32 of the upper supportelement 17, where it is fixed by a snapping action.

FIG. 13 illustrates the implant in its position fixed to the mitralvalve 7. The yarns 36 of the implant prevent the leaflet of the mitralvalve from prolapsing into the left atrium 5. After having fixed theimplant to the mitral valve 7 and after having sixed the yarns 36 to thenative leaflet in the region of its coaptation zone at 39, the shaft 28together with the tubular housing 29 are retracted according arrow 38.

The foregoing description and accompanying figures illustrate theprinciples, preferred embodiments and modes of operation of theinvention. However, the invention should not be construed as beinglimited to the particular embodiments discussed above. Additionalvariations of the embodiments discussed above will be appreciated bythose skilled in the art. For instance a second penetration of thenatural valve leaflet at the site of the coaptation (hinge point) forthe artificial network or valve structure fixes the atrially facingleaflet structure and separating from the coaptation front. Thissecondary fixation point can be measured individually and may beconstrued for the personalized diseased valve.

Therefore, the above-described embodiments should be regarded asillustrative rather than restrictive. Accordingly, it should beappreciated that variations to those embodiments can be made by thoseskilled in the art without departing from the scope of the invention asdefined by the following claims.

1. An implant for improving coaptation of an atrioventricular valve, theatrioventricular valve having a native first leaflet, a native secondleaflet and an annulus, the implant comprising a support structureconfigured to be arranged on and fixed to the annulus or to at least oneof the first and second native first leaflets, the implant furthercomprising retention means fixed to the support structure so as toprevent prolapse of the at least one native leaflet, wherein the supportstructure comprises an upper support element to be arranged on asuperior surface of the annulus or of the at least one native leafletand a lower support element to be arranged on an inferior surface of theannulus or of the at least one native leaflet, the upper and the lowersupport elements each comprising connection means cooperating which eachother for interconnecting the upper and the lower support element whileclamping a section of the annulus or of the at least one native leafletbetween the upper support element and the lower support element, whereinat least one connection means comprises a penetrating section configuredto penetrate the annulus or the at least one native leaflet for beingconnected with the other connection means.
 2. The implant of claim 1,further comprising a tubular housing, wherein the support structure andthe retention means are deployable from a first position, in which thesupport structure and the retention means are arranged within thetubular housing, into a second position, in which the support structureis deployed.
 3. The implant of claim 1, wherein the tubular housingcomprises two half-shells, a first half-shell housing the upper supportelement and a second half-shell housing the lower support element. 4.The implant of claim 3, wherein the upper and the lower support elementsare housed in the tubular housing in a separate, not interconnectedmanner.
 5. The implant of claim 3, wherein the first and secondhalf-shells are arranged at the distal end of a deployment instrument.6. The implant of claim 3, wherein the first and second half-shells arearranged to swing open in order to allow the implant to be deployed. 7.The implant of claim 1, wherein the lower support element carries atleast one holding arm for holding the retention means.
 8. The implant ofclaim 1, wherein the retention means, on one end thereof, are connectedto the lower support structure and, on the other end thereof, areconnected to the upper support structure.
 9. The implant of claim 1,wherein the retention means comprise a flexible net or a plurality offlexible wires or yarns.
 10. The implant of claim 1, wherein theretention means comprise an artificial leaflet arranged on the uppersupport element.
 11. The implant of claim 10, wherein the flexible net,wires or yarns are embedded into or fixed to the artificial leaflet. 12.The implant of claim 1, wherein the atrioventricular valve is a mitralvalve and the at least one native leaflet is a posterior leaflet of themitral valve.
 13. A method of improving coaptation of anatrioventricular valve, the atrioventricular valve having an annulus, afirst native leaflet and a second native leaflet, the method comprising:providing an implant comprising a support structure and retention meansfixed to the support structure, wherein the support structure comprisesan upper support element and a lower support element, the implant beingarranged in a tubular housing with the upper and the lower supportstructure being in a folded state, said tubular housing comprising afirst an a second half-shell, wherein the first half-shell houses theupper support element and the second half-shell houses the lower supportelement, advancing the tubular housing into the heart, swinging open thehalf-shells, advancing the tubular housing with the implant so that thefirst or the second native leaflet is arranged between the first and thesecond half-shells, unfolding the upper and the lower support structure,fixing the upper and the lower support structure relative to the annulusor to the first or second native leaflet, said fixing step comprisinginterconnecting connection means of the upper and the lower supportelements thereby clamping a section of the annulus or said first or thesecond native leaflet between the upper support element and the lowersupport element, wherein at least one connection means comprises apenetrating section that penetrates the annulus or said first or secondnative leaflet when being connected with the other connection means,positioning the retention means so as to prevent prolapse of the firstor second native leaflet, withdrawing the tubular housing from theheart.
 14. The method of claim 13, wherein the tubular housing isadvanced into the heart transatrially, transseptally, transfemorally ortransapically.
 15. The method of claim 14, wherein the step of fixingthe support structure comprises positioning the upper support element ona superior surface of the annulus or the native leaflet and positioningthe lower support element on an inferior surface of the annulus or thenative leaflet.
 16. The method of claim 13, wherein said fixing stepcomprises, before interconnecting the connection means, axially aligningthe connection means with each other by moving at least one of theconnection means relative to the other connection means.
 17. The methodof claim 13, wherein said step of interconnecting the connection meanscomprises moving the connection means towards each other by a closingaction of the half-shells.
 18. The method of claim 13, wherein said stepof positioning the retention means comprises adjusting a length of saidretention means between one end thereof, which is connected to the lowersupport structure, and another end thereof, which is connected to theupper support structure.
 19. The method of claim 13, wherein retentionmeans are used, the size and/or number of which is chosen to fit theindividual patient by measurements of the prolapsing areas of the nativevalve.
 20. The method of claim 19, wherein the size of the supportstructure, in particular of wing parts thereof, and/or the size of theretention means is calculated from the size of the prolapsing nativeleaflet part of the patient.
 21. The method of claim 13, wherein theretention means are fixed to the native prolapsing leaflet at thecoaptation line of the latter.